1. Field of the Invention
The present invention relates to a light source.
2. Description of the Related Art
In U.S. Pat. No 6,737,809 there is described and claimed:
1. A lamp comprising:
                (a) a waveguide having a body comprising a ceramic dielectric material of a preselected shape and preselected dimensions, the body having a first side determined by a first waveguide outer surface;        (b) a first microwave feed positioned within and in intimate contact with the waveguide body, adapted to couple microwave energy into the body from a microwave source having an output and an input and operating within a frequency range from about 0.5 to about 30 GHz at a preselected frequency and intensity, the feed connected to the source output, said frequency and intensity and said body shape and dimensions selected such that the body resonates in at least one resonant mode having at least one electric field maximum;        (c) an enclosed first cavity depending from said first surface into the waveguide body; and        (d) a first bulb positioned in the cavity at a location corresponding to an electric field maximum during operation, the bulb containing a gas-fill which when receiving microwave energy from the resonating waveguide body forms a light-emitting plasma.        
We name this lamp a ceramic waveguide lamp and have developed its technology and in particular have developed a matching circuit for matching the output impedance of a microwave source to the input impedance of the waveguide. This is described in our International Patent Application No PCT/GB2007/001935 (“the 1935 Application”). On entry to the UK national phase, under No GB 0820183.2 the main claim was amended as follows:
1. A lamp to be driven from a source of microwave energy, the lamp comprising:
                an electrodeless, discharge bulb,        a radiator for radiating microwave energy to the bulb,        a bulb receptacle formed of ceramic material coated with an electrically conductive shield, the receptacle having:                    a first recess containing the bulb, the recess being open to allow light to shine from the bulb and            a second recess containing the radiator, with the second recess being open to allow connection of microwaves to the radiator and                        a microwave circuit having:                    an input for microwave energy from the source thereof and            an output connection thereof to the radiator in the ceramic receptacle, wherein the microwave circuit is                        a capacitative-inductive circuit configured as a bandpass filter and matching output impedance of the source of microwave energy to input impedance of the circuit, receptacle and bulb combination.        